Many people really do find oral sex disgusting because the thought of putting their mouth on what we are told is a dirty place, bothers them- also the urine, blood, and potential infections your husband mentioned might also further this idea. Also, it is true that a higher sex drive might make certain things seem less disgusting and more appetizing, (can't spell)- and perhaps his age or medication is messing with his libido, causing him to think of the "ick" factor more, and it has nothing at all to do with you. However, as far as the risk factor, many people may not know that urine is actually extremely sterile, your menstrual blood is prob. only carrying the same diseases that you would pass through other sexual fluids during regular sex (such as healthy vaginal discharge), and infections carry tell tale signs that can be spotted. Also, your genitals, I am told, are cleaner than your mouth, which is supposedly the nastiest place on your body. If you have hpv in your genital region, I do believe it can migrate to your partner's throat, but they should be able to test you for that, and since it's an std, and you've been with him so long, chances are, he'd have that already, anyway, if you did.